/Engine/Plugins/Developer/AnimationSharing/Source/AnimationSharing/Public/AnimationSharingManager.h
Retrieves a blend instance, this could either mean reusing an already in progress one or a brand new one (if available according to scalability settings) returns whether or not the setup was successful
uint32 SetupBlend ( uint8 FromState, uint8 ToState, uint32 ActorIndex )